Tooling for industrial canning

ABSTRACT

A tool for seaming and sealing cans such as in the canning of food products. The can seaming tool includes a main pin having a spindle portion and a seam roll connected with the spindle so as to spin about the axis of the spindle. One or more bearing assemblies can be provided between the spindle and the seam roll to facilitate free spinning of the seam roll about the spindle of the main pin. The assembly includes the use of one or more O-rings between the main pin structure and the seam roll. The one or more O-rings advantageously seal the gap between the main pin and seam roll to prevent corrosive materials from the canning environment from entering the assembly and damaging interior components such as the bearing assemblies. This use of sealing O-rings greatly increases the life of the tooling and decreases cost and downtime.

FIELD OF THE INVENTION

The present invention relates to tooling for use in the canning of items such as fruits and vegetables and more particularly to tooling having improved lifespan and reliability.

BACKGROUND

Containers such as metal cans have been used for containing and storing items such as food products. When such cans are used to store food, various design requirements come into play, such as the use of food safe materials in the cans themselves and in the processing and tooling used to construct the cans.

The construction of such cans often involves the attachment of a lid to a previously formed cylindrical can body. The lid can be attached by a double seaming process wherein the lid and can body are tightly sealed to assure a strong airtight seal between the lid and can body. The lid edge and can body can be formed with a predetermined curved edge. The lid and can body are then processed by a first set of chucks and first set of rollers that curls edge of the lid over the edge of the can body. Then, the lid and can body can be pressed between a second set of chucks and a second set of rollers that squeeze the curled edges together to form a tight, secure seal between the lid and can body.

Tooling such has “P” model seaming machines produced by ANGELUS® has been used for some time, and machines such as these play a major role in the processing of tomato crops. Such tooling can be configured as three station (aka “three head”) seaming machines. The seamers typically close 60 to 100 cans per minute, depending on the size of the steam cookers used in the process.

The canning of certain food products presents even more specialized challenges. For example, when canning tomato products, the acidity of the canning environment causes quick corrosion of tooling used to seal the cans. In addition, the canning of tomato crops necessarily happens over a very short season of roughly three months. Therefore, there is a need to reduce the amount of down time and maximize speed of processing when canning such tomato products.

SUMMARY

The present invention provides a tool for seaming cans. The tool includes a pin structure, a portion of which defines a spindle. A seam roll is rotatably mounted on the spindle, with the seam roll and pin structure defining a gap between them. The tooling further includes one or more O-rings disposed within the gap between the seam roll and the pin structure.

The O-rings are placed advantageously to semi seal the gap between the pin structure and the seam roll so as to prevent corrosive environmental contaminates from entering the interior of the tooling and corroding or otherwise damaging interior components as well as to provide an escape to allow lubricant to be periodically added. This greatly increases the life of the tooling and prevents costly downtime in the canning process.

The tooling can also include one or more bearing assemblies located between the pin structure and the seam roll to facilitate the rotation of the seam roll on the spindle. The use of the above described O-rings prevents corrosive materials from entering the tooling and corroding the bearing assemblies. The bearing assembly can be a food-safe stainless-steel bearing. Or, for even further improved corrosion prevention, the bearing assembly can be one or more ceramic bearing assemblies, such as bearing assemblies that incorporate the use of ceramic balls enclosed in a housing. The invention can include a protective O-ring located at either end of the seam roll, and can include two O-rings fitted into a groove at one end of the seam roll.

The tooling assembly can be held together by a novel self-locking screw. The self-locking screw can include a head portion and a threaded shaft portion with a recess formed in the side of the threaded shaft portion. A polymer ball, such as a nylon ball can be fitted into the recess formed in the side of the threaded shaft portion of the screw. In use, the polymer ball engages the adjacent threads of the bore into which it is inserted, thereby preventing the screw from inadvertently coming loose. In use, the screw can be inserted and removed many times with the polymer ball remaining intact and providing effective protection against loosening of the screw. However, if the ball does eventually wear out, the ball can simply be removed from the screw and replaced at negligible time and expense. The screw can also be formed with an internal bore, which can extend through the screw and which can facilitate greasing of the tooling assembly without the need for disassembling the tooling.

These and other features and advantages of the invention will become apparent upon reading of the following detailed description of the embodiments taken in conjunction with the figures in which consistent reference numbering is used to indicate similar elements throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and advantages of this invention, as well as to illustrate the preferred mode of use, reference should be made to the following detailed description, read in conjunction with the accompanying drawings, which for clarity are not drawn to scale.

FIG. 1 is a schematic illustration of can seaming tooling;

FIG. 2 is an enlarged view of the can seaming tooling using a first set of can seaming rolls;

FIG. 3 is an enlarged view of the can seaming tooling using the first set of can seaming rolls after engagement of the first can seaming roll with a can base and can lid;

FIG. 4 is an enlarged view of the can seaming tooling using a second set of seaming rolls;

FIG. 5 is an enlarged view of the can seaming tooling after engagement of the second can seaming roll with the can base and lid;

FIG. 6 is an exploded view of a can seam roller assembly according to an embodiment of the invention;

FIG. 7 is a cross-sectional view of the can seam roller assembly of FIG. 6;

FIG. 8 is an exploded view of a can seam roller assembly according to another embodiment of the invention;

FIG. 9 is a cross-sectional view of the can seam rolling assembly of FIG. 8;

FIG. 10 is an exploded view of a can seaming tool according to another embodiment of the invention;

FIGS. 11a-11e are assembled views of the can seaming tool of FIG. 10 shown from various different perspectives;

FIG. 11d is a cross sectional view of the can seaming tool of FIGS. 11a-11e as seen from line 11 d-11 d of FIG. 11 a;

FIG. 12 is an exploded view of a can seaming tool according to yet another embodiment of the invention;

FIG. 13 is an assembled view of the can seaming tool of FIG. 12;

FIG. 14A shows views of a self-locking screw according to an embodiment as seen from various different angles;

FIG. 14B is a perspective view of the self-locking screw of FIG. 14A

FIG. 15 is a cross sectional view of the self-locking screw of FIGS. 14A and 14B; and

FIG. 16 is a top down view showing a head of the self-locking screw of FIGS. 14A, 14B and 15.

DETAILED DESCRIPTION

The following description is of the best embodiments presently contemplated for carrying out this invention. This description is made for the purpose of illustrating the general principles of this invention and is not meant to limit the inventive concepts claimed herein.

A can lid may be securely attached to a can body by a multi-stage seam rolling operation, such as that illustrated with reference to FIGS. 1-5. FIG. 1, shows a schematic illustration of an example of can seam tooling 100 for attaching a can end 102 to a can body 104. The can body 104 can be mounted on a lifter plate 106, and the can end 102 can be mounted on the can body 104. Then, as shown in FIG. 2, a seaming chuck 108 is fitted into a recessed part of the can end 102 so as to clamp the can body 104 and can end 102.

The tooling 100 can include a first set of seam rollers 110 that are formed with a first groove 112 and which is rotatably connected with a shaft 114, and a second set of seam rollers 116 having a second groove 118 and which are rotatably connected with a shaft 120. In a first seaming operation, the seaming chuck 108 is rotated about the axis 105 of the can body 104, while engaging the first seam roller 110 against the outer edge of the can end 102 as shown in FIG. 2. Then as shown in FIG. 3, the first seam roller 110 is moved toward the seaming chuck 108, causing the outer edge of the can end 102 to curl around the upper edge of the can body 102 as shown.

FIGS. 4 and 5 illustrate a second portion of the seam rolling operation. As shown in FIG. 4, a second seam roller 116 is engaged against the outer edge of the can end 102. Then, while rotating the seaming chuck 108 about the axis of the can body 104, the second seam roller 116 moved toward the seaming chuck 108. This second process folds the edges of the can end 102 into the edges of the can body 104, pressing them together and forming a secure, water tight, air tight seal between the can body 104 and can end 102.

One challenge that arises with the canning of certain food products is that of corrosion to canning tooling. This is especially problematic when canning acidic foods such as tomatoes. In addition, all products and tooling used in the canning process must be food-safe materials. This includes lubricants such as grease used to lubricate and protect the can seaming tooling during the seaming operation. In addition, many products such as produce products must be canned in a short window of time when the canned products are in season. For example, an entire year's tomato crop must be canned in a timeframe of about three months. This means that any downtime resulting from damaged or corroded tooling can lead to greatly increased cost and possibly crop spoilage. The present invention, embodiments of which are described below, prevents such corrosion or damage to tooling, even in highly corrosive, acidic environments while also maintaining food-safe standards.

FIG. 7 shows a cross sectional view of a seam roller assembly 602 according to an exemplary embodiment, and FIG. 6 shows an exploded view of the seam roller assembly 602. All components of the seam roller assembly 602 can be constructed of food safe, food grade materials. The seam roller assembly 602 includes a main pin 604 that has an end 606 that is configured to attach to other canning tooling (not shown) and has a shaft 607 at its opposite end. A seaming roll 608 attaches over the shaft 607 of the main pin 604 such that the shaft 607 of the main pin 604 acts as a spindle about which the seaming roll 608 can rotate. Therefore, the shaft 607 will be referred to herein as a “spindle” 607. A roller bearing 610 is located between the seam roll 608 and the spindle 607 of the main pin 604 so as to allow the seaming roll 608 to spin about a spindle 607 of the main pin 604. In this embodiment, the roller bearing 610 can include stainless steel components, such as stainless-steel rollers 611 (shown in FIG. 6). The roller bearing 610 can be separated from the shaft 607 of the main pin 604 by a roller bearing sleeve 612.

In addition to the roller bearing 610, the seam roller assembly 602 can include a pair of thrust bearings 614 to facilitate the spinning movement of the seaming roll 608, while holding the seaming roll 608 in the direction along the axis of the shaft 607. Thrust washers 616 can be provided adjacent to the thrust bearings 614 either on one side or both sides of each thrust bearing 614. For example, as shown in FIGS. 6 and 7 the inner thrust bearing 614 can have a pair of associated thrust washers 616 located at each side of the thrust bearing 614. The outer thrust bearing 614 can have a single thrust washer 616 located at an inner side of the thrust bearing 614 between the thrust bearing 614 and the roller bearing 610. In this case, a bottom cap structure 618 can secure the outer side of the adjacent thrust bearing 614. The bottom cap 618 can be securely held in place by a screw 620 that can be a flat head socket cap screw. The screw 620 can be constructed to have a novel, reusable, self locking feature that will be described in greater detail herein below.

Can seaming tooling is often used in corrosive environments. For example, the canning of acidic food products such as tomatoes results in a highly corrosive environment which can greatly reduce the lifespan of various components of a seam roller assembly, especially with regard to the roller bearing 610 and thrust bearings 614. In order to protect these components from corrosion, the seam roller assembly can be periodically injected with a food safe grease through an injection port, not shown. In previous seam roller tooling, this grease would quickly leak out, such as between the roller 608 and main pin 604, allowing corrosive external materials to enter into the seam roller assembly 602 and also requiring frequent re-application of grease. Both of which lead to increased downtime and decreased tooling lifespan.

The present invention, such as shown in the embodiment illustrated in FIGS. 6 and 7 avoids these problems, allowing for decreased downtime and greatly increased tooling life, even in highly corrosive environments. The roller assembly 602 includes one or more outer O-rings 620, and one or more inner O-rings. 622. The outer O-rings 620 are located within a gap between the main pin 604 and the seaming roll 608. The inner O-ring 622 is located at the shaft 607 of the main pin. In addition, an end cap O-ring 634 is located between the bottom cap 618 and seam roll 608. The O-rings 620, 622, 634 prevent the escape of lubricating grease from the assembly 602, and also prevent the entrance of corrosive environmental elements into the assembly 602, thereby preventing corrosion of the internal components of the assembly 602.

Because the seam roll 608 is designed to spin on the main pin 604, it would not be intuitive to use O-rings in the fashion illustrated and described with reference to FIGS. 6 and 7. While it might be thought that the use of such O-rings would prevent the free rotation of the seam roller 608, it turns out that with tight control of the size of the O-rings, effective sealing can be provided while also allowing the free rotation of the seam roll 608. Also, it is necessary that air and grease be able to escape from the assembly 602 when the assembly 602 is packed or re-packed with grease. Therefore, it is desirable that the O-rings 620, and 634 be sufficiently thick to prevent environmental elements from entering the assembly 602, and to prevent the free flow of grease out of the assembly 602. However, it is also desirable that the O-rings 620, 634 also be sufficiently thin and pliable that grease and air under pressure be able to escape past the O-rings 620, 634 (such as when packing the assembly 602 with grease as previously discussed).

The gap 624 located at the outer diameter of the seam roller 608 and main pin 604 is the entrance point that is most susceptible to the entrance of corrosive environmental contaminants. Therefore, as shown in FIGS. 6 and 7, it may be preferable to include multiple (e.g. 2) O-rings 620, at this outer location.

With continued reference to FIG. 7, it can be seen that the main pin 604 has an outer flange portion 626 that supports and partially contains the seam roll 608. It can also be seen that the outer flange portion itself has an outer portion 628 that wraps around an outer diameter portion of the seam roll 608. The outer flange portion 628 and seam roll 608 are configured such that the gap 624 between them has a portion 630 that is substantially parallel with the axis of the main pin shaft 607 as shown. This gap portion 630 is also formed with a groove 632 into which the O-rings 620 fit and which holds the O-rings 620 securely in place during operation of the assembly 602. Similarly, the bottom cap 618 has a groove formed in its inner side near its outer diameter as shown in FIG. 7. This groove securely holds the O-ring 634 during operation.

The use of O-rings 620, 622 in can seam rolling tooling as described above has never before been contemplated or used in the can seaming industry. This improvement in the design of a can rolling assembly tool 602 greatly increases the life of the tool during use. In addition, this design greatly reduces process down-time which would otherwise be necessary to replace the seam rolling tool, replace bearings within the seam rolling tool or to re-grease the tool. The use of such a design has been shown to provide on the order of a 20-fold increase in uninterrupted operation time. In addition, this improvement can be realized with minimal additional manufacturing cost.

FIGS. 8 and 9 illustrate a seam rolling assembly 802 according to another embodiment of the invention. The assembly 802 includes a main pin 804 that includes an outer end 806 configured to attach to seam forming tooling (not shown). The main pin 804 also includes a spindle portion 808 and a flange 810 located generally between the outer end 806 and spindle 808.

The assembly 802 also includes a seam roll 812 that is configured to spin about the spindle 808 of the main pin 804. First and second bearing assemblies 814, 816 are disposed about the spindle 808 (between the spindle 808 and seam roll 812) to facilitate the spinning of the seam roll 812 about the spindle 808. In this embodiment, the bearing assemblies 814, 816 are preferably ceramic bearing assemblies that each can include a ceramic ball 818 held within a casing 820. The use of ceramic bearings in the assembly 802 further prevents damage to the bearings 814, 816 from use in a corrosive environment. The ceramic materials are essentially inert and not susceptible to corrosion such as from an acidic environment.

A bearing spacer 822 in the shape of a washer can be inserted between the bearing assemblies 814, 816 to maintain a desired spacing between the bearing assemblies 814, 816. A screw 824, screws into a threaded opening in the spindle 808 of the main pin 804. The screw is preferably a flat head socket cap screw having an interior bore that extends through the screw 824. A contoured washer 826 is disposed between the screw 824 and bearing assembly 816. As can be seen, the screw 824 presses the bearing assemblies 814, 816 against the flange 810 of the main pin 804, thereby securely holding the bearing assemblies 814, 816 within the assembly 802. A snap ring 828 fits into a space between the securely held bearing assemblies 814, 816 and into a slot in the inner diameter of the seam roll 812. This effectively holds the seam roll 812 in place, preventing movement of the seam roll 812 in a direction parallel with the axis of the spindle 808. Movement of the seam roll 812 in a lateral direction (perpendicular to the axis of the spindle 808) is limited by engagement with the outer portion of the bearing assemblies 814, 816, while also allowing the seam roll 812 to spin freely about the spindle 808.

A bottom cap 830 fits into the end of the seam roll 812, and is securely held in place by a spiral retaining ring 832. In FIG. 9 it can be seen that the screw 824 has a hollow interior with a bore that extends through the screw. It can also be seen that the main pin 804 also has a hollow interior that extends through the length of the main pin 804. These hollow bores in the main pin 804 and screw 824 can facilitate the greasing and re-greasing of the assembly 802. To do so, a food safe grease can be entered into the end of the main pin 804 as indicated by arrow 834. This grease can then travel through the screw and into the interior of the assembly 802, where it can lubricate the various components including the bearings 814, 816.

With continued reference to FIGS. 8 and 9, the assembly 802 includes one or more O-rings 836 at a first end 840 of the seam roll 812 and one or more O-rings 838 at a second end 842 of the seam roll 812. In the example illustrates, there are two O-rings 836 at the inner end (or what will be the upper end during operation) 840 and only one O-ring 838 at the outer (or lower) end 842. This can be a preferred arrangement, since the gap at the upper end 840 is a more likely entrance point for corrosive contaminates, than is the outer (or lower end) 842. For example, as can be seen, at the first end 840, the O-rings 836 are located in a gap between the main pin 804 and the seam roll 812, and these two elements move relative to one another as the seam roll spins about the spindle 808. At the other end 842, however, the seam roll 812, bottom cap 830, and O-ring 838 all move together as a fixed unit. Therefore, although there is some chance of contaminates entering the assembly 802 through the outer end 842, there is less likelihood of contaminates entering at this point than at the inner end 840.

As with the previously described embodiment, the O-rings 836, 838 are sufficiently thin and flexible to allow air and grease to escape past them when under pressure such as during the previously described grease packing operation. However, the O-rings 836, 838 are also sufficiently thick and firm to prevent grease from passing through them when not under significant pressure during operation and also to prevent contaminates, from entering the assembly 802 during operation.

The flange 810 of the main pin 804 has an outer portion that wraps around an outer diameter of the seam roll 812 to form a gap between the seam roll 812 and flange 810 at least a portion of the gap being oriented parallel with the axis of the spindle 808. As with the previously described embodiment, the O-rings 836 can be located in this parallel gap portion. This portion of the flange 810 can be formed with a groove into which the O-rings 836 securely sit. At the other end, the bottom cap 830 can be formed with a bent tab at its outer end that also defines a gap between the cap 830 and seam roll 812 that is oriented substantially parallel with the axis of the spindle 808. The seam roll 812 can be formed with a groove at its inner circumference in which the O-ring 838 can securely sit.

FIGS. 10 and 11 illustrate canning tooling 1000 according to yet another embodiment. FIG. 10 is an exploded view of the canning tooling 1000 and FIGS. 11a-11d are various views of the assembled canning tooling 1000. FIG. 11a is a first end view of the canning tooling 1000 showing a cap and screw which will be described in greater detail herein below, and FIG. 11e is an opposite end view showing a main pin which also will be described in greater detail herein below. FIG. 11e shows a side view of the canning tooling 1000 and FIG. 11d is a cross sectional view of the canning tooling 1000 as seen from line 11 d-11 d—of FIG. 11 a.

With reference to FIG. 10, the canning tooling 1000 includes a main pin 1002 that includes an outer end 1004 configured to attach to seam forming tooling (not shown). The main pin 1002 also includes a spindle portion 1006 and a flange 1004 located generally between the outer end 1004 and spindle 1006.

A seam roller 1012 is configured to fit over the spindle 1006. The seam roller 1012 has an outer profile that is configured to a desired shaping function to deform can and lid ends in a desired manner such as described above with reference to FIGS. 1 through 5 and has an inner bore that is configured to fit over the spindle 1006 of the main pin 1002.

The seam roller 1012 rides on a roller bearing 1014 which fits between the spindle 1006 of the main pin 1002 and the inner bore of the seam roller 1012. The roller bearing 1014 advantageously is constructed of stainless-steel components, such as stainless-steel rollers 1016. Stainless steel components have not previously been used in canning tooling, because of the added cost and manufacturing complexity. Stainless-steel is a hard metal and, therefore, difficult to machine. In addition, the use of stainless-steel components increases manufacturing cost, because of the added cost of the metal itself. However, the inventors have found that the use of stainless-steel bearing components, surprising, decreases cost in the long run due to the greatly increased lifespan of the product and greatly reduced need for frequent maintenance of the tooling. As previously discussed, canning tooling is often operated in harsh corrosive and messy environments. Environmental contaminants such as acidic tomato and other fruit juices quickly corrode the components of the canning tooling. In order to prevent this, prior art tooling must be frequently maintained, such as by re-greasing the tooling, and by costly replacement of damaged and/or corroded parts. This results in expensive manufacturing down time, which is very disruptive, and increases processing cost. Even in spite of this frequent re-greasing, the internal components of prior art tooling corrode and fail, leading to further increased cost in the long run. The inventors have found that, by using stainless steel bearing components (e.g. stainless-steel roller bearing 1014), the increased cost of the stainless-steel components is more than offset by the long life and low required maintenance and down-time of the tooling.

With continued reference to FIG. 10, the tooling 1000 further includes a thrust bearing 1018 and a thrust washer 1020. The thrust bearing 1018 is disposed between the roller bearing 1014 and the flange 1010 of the main pin 1002, and the thrust washer 2020 is disposed between the thrust bearing 1018 and the roller bearing 1014 in order to give the end of the roller bearing 1014 a solid surface against which to press. As with the roller bearing 1014, the thrust bearing 1018 can be constructed of stainless-steel components, which provides the advantage described above with regard to tooling life and reduced maintenance requirements.

The seam roller 1012, bearings 1016, 1018 and washer 1020 are held in place over the spindle 1006 by a bottom cap 1022 and self-locking screw 1024. The screw 1024, which will be described in greater detail herein below, is configured to thread into a threaded interior bore 1028 of the main pin 1002. The cap 1022 is configured to engage the outer end of the seam roller 1012.

When, the tooling 1000 is assembled, as shown in FIGS. 11a-11d , it can be seen that the seam roller 1012 is securely held between the cap 1022 and the flange 1010 of the main pin 1002. When assembled, the tooling 1000 can be packed with a food-safe grease by inserting such grease under pressure through the bore of the main pin 1002 as indicated by arrow 1030 in FIG. 11d . The assembled tooling 1000 can be thusly packed with grease until grease is seen to emerge between the cap 1022 and seam roller 1012. During operation, the seam roller 1012 will ride on the roller bearing 1016 and thrust bearing 1018, the seam roller 1012 will ride on a thin film of grease between the seam roller 1012 and cap 1022 (as the cap 1022 does not rotate with the seam roller 1012). However, during operation, the forces of the seam roller operation will tend to force the seam roller 1012 against the spindle of the main pin 1002 and against the flange 1010 of the main pin 1002, the direction vector of this force being indicated by arrow 1032. Therefore, it can be seen that the seam roller 1012 is pushed away from the cap 1022 during operation rather than toward the cap 1022. For this reason, the thin film of grease provides ample freedom of movement between the seam roller 1012 and cap 1022 without the need for an additional thrust bearing at this end of the assembly.

With reference to FIG. 10, in an optional additional embodiment, the assembly 1000 can employ a dual profile seam roller 1034. This dual profile seam roller 1034 can provide a second profile as a back-up profile at each end to allow for seaming processes to be performed with a single seaming roll. In order to use the tooling for a continued seam rolling operation, the tooling can be disassembled and the orientation of the seam roller can be flipped 180 degrees to allow the second seaming profile to engage the can lid and body.

In addition, in another possible embodiment the screw can be formed as a pilot screw 1036 to facilitate manual engagement into the tooling 1000. The pilot screw 1036 has a reduced diameter portion 1038 at the end of the threaded portion of the screw 1036. This allows an operator to easily insert the screw 1036 into the tooling 1000 by hand prior to tightening.

FIGS. 12 and 13 illustrate can seam tooling 1200 according to yet another embodiment of the invention. The can seam tooling 1200 includes a main pin 1202 that has a first end 1204 that is configured to screw securely into canning tooling, and a second opposite end that is configured as a spindle 1208. A flange 1206 is formed between the first end 1204 and spindle 1208.

First and second bearing assemblies 1210 are configured to fit over the spindle 1208. The bearing assemblies are preferably ball bearing assemblies that are configured withstand a thrust load in a direction that is parallel with the longitudinal axis of the spindle 1208. The bearing assemblies can include ceramic balls 1302 (FIG. 13), which can be held securely within a housing 1304. The bearing assembly 1210 can be configured with an inner diameter to allow it to be press fit onto the spindle 1208 of the main pin 1202, thereby allowing for secure engagement with the main pin 1208.

A seeming roll 1212 fits over the bearing assemblies 1210 so as to spin freely about the spindle 1208. A bearing spacer 1214 in the form of a washer is disposed between the bearing assemblies 1210 to maintain a desired separation between the bearing assemblies 1210 at their inner diameters. In addition, a snap ring 1216 is located between the bearing assemblies at their outer diameter. As can be seen in FIG. 13, the snap ring fits into a groove that is formed at an inner diameter of the seaming roll 1212. Therefore, it can be seen that the snap ring prevents relative movement between the seaming roll 1212 and the bearing assemblies 1210, in a direction parallel with the longitudinal axis of the spindle 1208.

A screw 1218 is configured to screw into a threaded interior bore of the main pin 1202. The screw 1218 can be a self-locking, flat head, socket screw, and can be configured with an internal bore that extends through the screw 1218. The screw 1218 holds the bearing assemblies 1210 securely on the spindle 1208 by holding the bearing assemblies 1210 against the flange 1206 of the main pin. A formed spacer 1220 can be provided between the screw 1218 and the nearest bearing assembly 1210. Because the longitudinal movement of the seaming roll 1212 relative to the bearings 1210 is prevented by the snap ring 1216, the seaming roll 1212 remains securely held on the main pin 1202 while being free to rotate.

A bottom cap 1222 is formed to cover the end of the seaming roll 1210. As can be seen, in this embodiment, the screw 1218 is inside the assembly relative to the cap. The cap 1222 can be formed to snap fit into the end of the seaming roll and can be further held in place by a spiral retaining ring 1224 which fits into a groove in the inner diameter of the outer end of the seaming roll 1210. An optional “O” ring 1226 can be located between the cap 1222 and the seaming roll to seal the space between the cap 1222 and the seaming roll 1210.

In order to lubricate the assembly 1200, grease can be injected under pressure into the bore within the end 1204 of the main pin 1202 as indicated by arrow 1306. In FIG. 13 it can be seen that the screw 1218 also has an interior bore that extends through the length of the screw 1218. The injected grease can pass through the interior bore of the main pin 1202, and also through the interior of the screw 1218.

As can be seen in FIG. 13, the cap 1222 is formed so as to create a space 1308 between the cap 1222 and the screw 1218 and bearing assembly 1210. This advantageously creates a reservoir which can fill with the injected grease. As the grease is injected through the main pin 1202 and screw 1218, it will pack the entire interior of the assembly 1200 with grease, including packing the bearings 1210 with grease. In addition, however, the reservoir 1308 will also fill with additional grease. This creates a reserve of grease to ensure effective lubrication of the bearing assemblies 1210 over a greatly increased duration of use of the tooling assembly 1200. This reservoir 1308, therefore, greatly increases the lifespan of the tooling assembly and also greatly increases the amount of time that the tooling 1200 can be used before it has to be re-packed with grease. This improves production throughput by greatly decreasing tooling downtime.

With reference to FIGS. 14A-16, a novel self-locking screw 1402 is described. This screw 1402 can be used as the screw 824 of FIGS. 8 and 10, as the screw 620 of FIGS. 6 and 7, as the screws 1024, 1038 of FIGS. 10 and 11 or as the screw 1218 of FIGS. 12 and 13. The self-locking screw 1402 is shown as viewed from various angles in FIG. 14A, in a perspective view in FIG. 14B and in cross-section in FIG. 15. The screw 1402 can be formed of a metal and includes a threaded shaft portion 1404 and a head portion 1406. The threaded portion 1402 can be machined to include any of various forms of threads. The threaded portion 1404 of the screw 1402 is formed with a recess 1414 in its threaded side which can be more clearly seen with refence to the cross-sectional view of FIG. 15. The recess 1414 is configured to receive and securely hold a ball 1408, as can be seen with reference to FIG. 14. The ball 1408 can be formed of various polymer materials, but is preferably constructed of nylon which has been found to provide good results at minimal cost. The size of the recess 1414 and ball 1408 are chosen to allow the ball 1408 to be pressed into the recess and to also allow the ball to be securely held within the recess 1414.

When in use, the ball 1408 provides a pliable consistent friction against a threaded opening into which the screw 1402 is fastened. This friction between the ball 1408 and the adjacent threads of the opening (not shown) into which the screw is inserted ensures that the screw will remain securely engaged within the opening. Testing has shown that the screw 1402 can be used for many cycles with a single ball 1408. That is, the screw 1002 can be screwed into a threaded opening, removed, and reinserted many times with the ball 1008 remaining intact and securely holding the screw in place. However, if at some time the ball 1408 becomes worn and ineffective, it can easily and inexpensively be removed and replaced with a new polymer (e.g. nylon) ball 1408, at which time that screw 1402 can continue use for many more applications. A self-locking screw 1402 such as that described provides an extremely cost effective solution compared with other previously used locking screw devices. The screw not only provides a self-locking feature at greatly reduced expense, but also provides the additional benefit of being able to be used for many fastening cycles and provides the added advantage that the polymer ball 1408 can be replaced after many cycles of use.

In addition, the screw has a novel head 1406, which can be understood more clearly with reference to FIGS. 14A and 14B, and also with reference to FIG. 16 which shows a top down view of the head 1406 of the screw 1402. As can be seen in FIG. 14B and FIG. 16, the outer portion of the top of the head 1406 of the screw 1402 is configured with a knurled texture 1410. This knurling 1410 facilitates manual manipulation of the screw to allow the screw to be threaded into a corresponding threaded opening by hand prior to further tightening by use of tooling such as a wrench (e.g. Allen wrench). This knurling is especially beneficial for use in the above described tooling applications, such as described above with reference to FIGS. 6-13. As described above, the canning tooling is generally operated in an environment which includes grease caustic acidic chemistries that can include, for example, tomato juice and other liquids. Operators must be able to remove and reinstall the screw 1402 easily and accurately in order to maintain the tooling and also to switch out various roller configurations. Starting the threading of the screw 1402 into a threaded opening is preferably performed by hand so as to prevent cross threading of the screw into the opening. As those skilled in the art will understand, cross-threading of the screw into the opening can cause catastrophic damage to the screw and also to the rest of the tooling. However, manually handling the screw can be difficult, especially in the above described wet, greasy and acidic environment. The knurling 1410 of the head 1406 of the screw 1402 greatly facilitates manual gripping of the screw during the manual insertion of the screw into the appropriate threaded opening.

The screw 1402 can also be configured with a pilot end 1412 as shown in FIG. 14B. The pilot end 1402 is a reduced diameter portion at the end of the screw 1402, which facilitates fitting the screw into the appropriate opening manually prior to tightening with a wrench.

While various embodiments have been described above, it should be understood that they have been presented by way of example only and not limitation. Other embodiments falling within the scope of the invention may also become apparent to those skilled in the art. Thus, the breadth and scope of the invention may also become apparent to those skilled in the art. Thus, the breadth and scope of the inventions should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents. 

What is claimed is:
 1. A tool for sealing cans, the tool comprising: a pin structure having a portion of which defines a spindle; a seam roll mounted for rotation about the spindle, the pin structure and the seam roll defining a gap between them; and at least one O-ring disposed in the gap between the pin structure and the seam roll.
 2. The tool as in claim 1 further comprising a plurality of O-rings.
 3. The tool as in claim 1 wherein the at least one O-ring includes a first O-ring located at a first end of the seam roll and a second O-ring located at a second end of the seam roll.
 4. The tool as in claim 1 further comprising a pair of O-rings located at a first side of the seam roll and a third O-ring located at a second side of the seam roll.
 5. The tool as in claim 1, a groove formed in the seam roll, the groove being configured for holding the O-ring.
 6. The tool as in claim 1 further comprising at least one bearing assembly located between the spindle and the seam roll for facilitating the rotation of the seam roll about the spindle.
 7. The tool as in claim 6 wherein the bearing is a roller bearing that includes stainless steel rollers.
 8. The tool as in claim 6 wherein the bearing further comprises ceramic components.
 9. The tool as in claim 1, further comprising a flange formed on the pin, and wherein the O-ring is located between flange and a portion of the seam roll.
 10. The tool as in claim 1, further comprising a flange formed on the pin, wherein the flange wraps around a portion of the seam roll forming a gap portion that is substantially parallel with an axis of the spindle and wherein the O-ring is located within the gap portion.
 11. The tool as in claim 1 further comprising at least one bearing assembly located between the spindle and the seam roll for facilitating the rotation of the seam roll about the spindle, and further comprising a screw configured to engage an interior bore of the pin and configured to hold at least one bearing assembly and seam roll in place on the spindle.
 12. The tool as in claim 11, wherein the pin and screw each have an interior bore through which grease can flow to apply grease to an interior of the tool.
 13. The tool as in claim 11, wherein the screw has a threaded portion with a recess formed into the threaded portion and a polymer ball inserted into the recess.
 14. The tool as in claim 1, wherein the at least one O-ring is configured to allow passage of air and grease under pressure, but to prevent the flow of environmental contaminants into the tool, and to prevent the flow of grease out of the tool when the grease is not under significant pressure.
 15. A self-locking screw, comprising: a screw body having a threaded shaft portion and a head portion; a recess formed in the threaded shaft portion; and a polymer ball fitted into the recess in the threaded shaft portion.
 16. The self-locking screw as in claim 15, wherein the polymer ball is formed of nylon.
 17. The self locking screw as in claim 15, wherein the screw body has an internal bore that extends through the length of the screw body.
 18. The self locking screw as in claim 15 wherein the recess has a cylindrical shape.
 19. The self locking screw as in claim 15 wherein the recess has a semi-spherical shape.
 20. The self locking screw as in claim 15 wherein the head is formed with a knurled texture. 